Saturday, 2 February 2013

Owl Pellets


We have a wild barn owl living at the Centre. She has been here for some time, but recently she has spent a couple of evenings under one of our awnings and so I have had a chance to look at her owl pellets... If you have never looked at an owl pellet before, give it a go... it is an amazing thing to do and I still enjoy it as much today as I did when I was younger.

Above is a barn owl pellet, recognisable due to the darkness of it. Now some people like to soak the owl pellet first before dissecting it. If you wanted to do this, the best way is to place it in a shallow bowl of water with a drop of washing up liquid in it. Leave it for an hour or two and it will start to break up on its own... However, I prefer just to get stuck straight in.


You don't know what you are going to find, so best to where thin gloves. Slowly prize the owl pellet apart with your fingers. What you are looking for is any small bones inside.



You will find there are quite a few in each pellet, such as this one above. Carefully pull these bones out cleaning them as best you can, and place them somewhere safe.



What you are hoping for are either the jaw bones, or skulls of an animals... this will give you the best chance of identifying what the owl ate the previous night.



Above is a couple of skulls found in a pellet a few years ago, you can see the right skull is still fully intact.



Once you have separated out all the bones, you will be left with two piles. The above is all the fur of the owls meal which it couldn't digest, which sometimes can give you an idea of what it may have been, but really it is the second pile you need to look at.



All of these bones where found in the one pellet. You can see all types of bones in there, the smaller ones at the bottom are vertebrae of the backbone. The little thin ones are ribs ,and the odd shaped thin ones on the left are from the skull caps. The larger bones at the top show the shin bone, hip bone, shoulder blade, upper arm, thigh and forearm. The most exciting though are the skulls and jaw bones...

This shows that this owl ate three mammals the previous night. The two larger skulls on the left are from voles and the smaller skull on the right is from a shrew.



From the skulls you can work out whether it is a mouse, vole or shrew. Then from the teeth you can even work out if it is a bank or field vole, a house, wood or harvest mouse or a water, common or pygmy shrew. Difficult unless you know what your looking for, as it is all to do with the ridges and roots of the teeth!

The photo above is a real find. It is a shrew... You can tell it is a shrew from the shape of the skull and the insectivorous teeth. I don't think you will be able to see on the photo, but you can even tell it is a pygmy shrew due to the spacing of the cusps on the lower front tooth.

Even more exciting, and I hope it shows on the blog, but you can see the red tips to the teeth that many shrews have! Why do they have red teeth?... Well it's iron deposits in the enamel, making the teeth harder for all the eating shrews have to do to stay alive, and to help break through what they do eat. Cool huh?


1 comment:

  1. I've always wanted to do that! Amazing what you can finding a pellet!n Great post.

    ReplyDelete